1. Technical Field
The invention relates generally to error correction and digital communication systems; and, more particularly, it relates to employing interleaving (and/or de-interleaving) in combination with applications of error correction codes.
2. Related Art
Previous interleavers are typically employed to try to combat the noise problems associated with communication of information (data) across a communication channel. One particularly problematic noise problem is that attributed to burst noise error. This burst noise error is typically not purely Gaussian, which often makes dealing with it significantly difficult when compared to Gaussian types of noise. Impulse actions within the communication channel, which may arise from a whole host of events, are very problematic, in that, they may wipe out entire blocks of data. In some situations, this may not be problematic. Depending on the channel capacity and data transmission rates involved, some burst error can actually corrupt data that is longer than a code word length. For example, an impulse action, when corrupting a relatively long portion of data, may cause burst error over a portion of data that is much longer than that which a code word may correct. This is especially problematic as data transmission rates across communication links continue to increase; where a particular event (that is relatively lone with respect to the channel capacity and data rates involved) may wipe out even more blocks of data. In addition, impulse noise problems are typically not purely Gaussian in nature; this characteristic makes dealing with them oftentimes much more difficult, in dealing with these impulse noise problems, than in dealing with other noise types that have typical Gaussian distributions.
In the communication context, one effort to combat this problem is to try to employ some error correction codes, so that the actual signal may be retrieved even in the event that some error is introduced during the data's transmission over the communication channel. Then, in the receiver side, the error correction is performed. Numerous types of error correction exist, as understood by those persons having skill in the art, including block error correction codes and convolutional error correction codes and other types. In addition, if the duration of an impulse noise source is too long, then any of these previous error detection and correction schemes simply cannot perform the correction. The data will simply be lost.
One method that has been developed to try to combat these problems has been to interleave the data at the transmitter side of the communication channel before transmitting it over the communication channel to the receiver side. Interleaving may be viewed as trying to permutate the data at one end of the communication channel, so as to try to achieve the situation where block of data that is corrupted by the communication channel may be interleaved throughout many code words of the data; it may be viewed an effort to reduce the probability that entire blocks of data may be lost during the communication through the communication channel. Then, at the other side of the communication channel, any corrupted data will, hopefully, be able to be corrected to ensure that whole sections or blocks of the data are not lost. Ideally, using interleaving and error correction techniques in combination, the bit error rate of the communication channel will ideally be reduced.
However, while many prior art interleaving methods do effectively reduce bit error rates, their implementation typically requires many registers and memory to achieve their proper operation. Here, there is a situation where interleaving has been introduced to try to assist the error correction techniques, in trying to preserve the data to an even greater extent, yet the inefficiencies and the processing-consumptiveness of various previous interleaving schemes often prohibit their very implementation.
Further limitations and disadvantages of previous, conventional, and traditional systems will become apparent to one of skill in the art through comparison of such systems with the invention as set forth in the remainder of the present application with reference to the drawings.